旋转剪切式青花椒采摘装置设计与试验

Design and experiment of the rotating shear picking device for green Sichuan peppers

针对基于“下桩”采摘方法的青花椒采摘设备存在喂入困难、易堵塞而造成采摘效率低的问题,该研究设计了一种旋转剪切式青花椒采摘装置。首先基于花椒枝物理、力学特性确定旋转剪切式青花椒采摘过程包括花椒枝旋转驱动、花椒枝导向喂入和剪切采摘,剪切采摘功能由往复式切割器实现。并设计双动刀往复式切割器及其传动机构,确定了剪切采摘装置的结构和运动参数。进一步地,运用ANSYS/LS-DYNA构建花椒枝剪切仿真模型,确定最优齿形参数为:刀齿切割角20°,刀齿刃角50°,刀齿厚度2.5 mm,该条件下峰值切割力为3.739 N。最后通过单因素试验确定了花椒枝喂入角度、花椒枝喂入速度、花椒枝旋转速度的取值范围分别为40°~60°、20~40 mm/s、20~40 r/min;并采用BoxBehnken设计法制定三因素二次回归正交组合试验方案,运用Design-Expert 12对试验结果进行方差分析和响应面分析,得到旋转剪切式青花椒采摘装置的最优工作参数为:花椒枝喂入角度55°,花椒枝喂入速度33.21 mm/s,花椒枝旋转速度30 r/min;通过试验验证得出在最优工作参数下,单人单枝喂入时青花椒平均采摘效率为10.95 kg/h,平均采净率为95.57%,平均伤果率为12.87%。研究结果可为青花椒采摘机的研发提供技术参考。

Feeding difficulty and easy clogging have confined the picking efficiency of green Sichuan pepper,leading to the“pile picking”.In this study,a rotating shear picking device was designed for green Sichuan pepper.Firstly,a picking scheme was determined,according to the physical and mechanical properties of prickly ash branches.The specific procedures included the rotating drive,guide feeding,and shearing picking of prickly ash branches.The reciprocating cutters were selected to realize the shear picking.The double-action reciprocating cutters were also designed for their transmission.The structure and motion parameters were determined to meet the requirements of rotary shear picking.Secondly,the simulation model was established to shear the prickly ash branch using ANSYS/LS-DYNA.The orthogonal tests were carried out with the cutting angle of the cutter tooth,the edge angle of the cutter tooth,and the thickness of the cutter tooth as the control factors,while the peak cutting force as the evaluation index.The results showed that the optimal tooth parameters were the cutting angle of 20°,edge angle of 50°,and tooth thickness of 2.5 mm,with the peak cutting force 3.739 N,which was fully met the requirements of shear picking for the green Sichuan pepper.Finally,the prickly ash branches with fresh green Sichuan pepper were piled in the Sansheng Town,Beibei District,Chongqing,China,in June,2023.A single-factor experiment was carried out with the branch feeding angle,branch feeding speed,and branch rotational speed as the control factors,while the picking efficiency,net collection rate,and fruit injury rate as the evaluation indices.The branch feeding angle,branch feeding speed,and branch rotation speed were determined in the range of 40°-60°,20-40 mm/s,and 20-40 r/min,respectively.A three-factor quadratic regression orthogonal combination test was analyzed using Box-Behnken design on the Design-Expert 12.The optimal operating parameters were achieved in the branch feeding angle of 55.035°,the branch feeding speed of 32.04 mm/s,and the branch rotation speed of 29.635 r/min,in the rotating shear picking device for green Sichuan pepper.The performance was predicted as the picking efficiency of 10.78 kg/h,the net collection rate of 95.66%,and the fruit injury rate of 12.06%.The optimized parameters were rounded as the branch feeding angle of 55°,the branch feeding speed of 33.21 mm/s,and the branch rotational speed of 30r/min for the prototype test.Experiment validated that the average picking efficiency of a single person feeding a branch for the green Sichuan pepper was 10.95 kg/h using optimal operating parameters,with an average net collection rate of 95.57%,and an average fruit injury rate of 12.87%.The finding can provide the technical references to develop the picking machines for green Sichuan pepper.